Pope Benedict XVI urged Czechs on Sunday to "return to God" during a mass in the Czech Republic that was attended by an estimated 120,000 people. The mass was the highlight of the pontiff's three day visit to the strongly secular nation.

The pope and thousands of pilgrims sang and prayed at an airfield in the southeastern city of Brno, during an open air mass aimed at encouraging the Czech Republic to return to its Christian traditions.

His comments came as researchers note that the Czech Republic is among the most atheistic nations in Europe, with nearly half of its citizens claiming to be non-believers.

Pope Benedict told the cheering worshipers, many of whom waved Vatican and Czech flags, that "History has demonstrated the absurdities to which man descends, when he excludes God from the horizon of his choices and actions."

The papal mass also included pilgrims from neighboring Germany and Austria.

Speaking in his native German, Pope Benedict said he was pleased they came to worship with what he called their "Czech brothers and sisters". He said it is especially important in these turbulent times to spread the Catholic gospel.

Sunday's open air mass was the highlight of the pope's visit to the Czech Republic, which marks 20 years since the fall of communist governments in Eastern Europe that persecuted the Roman Catholic Church.

Communists, who seized power throughout the region after World War II, including what was then Czechoslovakia, confiscated church-owned properties and persecuted priests.

On Saturday, the pontiff spoke of his sorrow over what he called "the wounds" of decades of atheistic communism. He told diplomats and politicians in Prague to reach out with Christian values to the nation's young generation.

"I warmly encourage parents and community leaders to expect authorities to promote the values which integrate the intellectual, human and spiritual dimensions worthy of the aspirations of our young," he said.

The Vatican's envoy to the Czech Republic, Archbishop Diego Causero, said the pontiff hopes his trip will help to overcome Czech mistrust of organized religion.

"Now the [Catholic] Church suffered a lot during the years of Communism, especially in the Czech Republic. Also, many of the present bishops have been imprisoned," said Causero. "In the last 20 years, of course, there was a kind of happiness; the walls came down. But in spite of that, the Church didn't find a proper way to present itself. The Church is still viewed as a sort of enemy of the Czech people by a good majority."

This is the Catholic leader's first tour of the Czech Republic since becoming pope.

His Polish predecessor, John Paul II, visited Czechoslovakia three times and is often regarded as having played a key role in the region's struggle against communist rule.

On Monday, the pope is scheduled to visit the Basilica of St. Wenceslas in the town of Stara Boleslav, a popular pilgrimage destination, northeast of Prague. He is due to return to Rome later Monday after meeting with Czech bishops.